US2869639A - Stop clock reset mechanism - Google Patents

Description

Jan. 20, 1959 Filed July 8, 1954 J. J. AMBROZAITIS STOP CLOCK RESET MECHANISM 3 Sheets-Sheet 1 I ai s I )4 40 58 fici. 1.

INVENTOR.

Js/m d Ambroza/f/s AGEN T.

J. J. AMBROZAITIS STOP CLOCK RESET MECHANISM Jan. 20, 1959 3 Sheets-Sheet 3 Filed July 8, 1954 WA\\\\.M\\\\-\\\\\\-\\X\\\\\\\\\\\\ Wm H U H 1 .1 s H 1 a V\ m 4 B M s H A i a m m m u M flop H w H w H H H r H w\\ \7 H H M H n w MN 1 IN V EN TOR. /o/m fllmra 24/ f/s AGINI:

Un S ew Pe m? r 2,869,639 ISTO'P CLOCK RESET MECHANISM John J. Ambrozaitis, Waterbury, Conn., assignor, by

mesne assignments, to Consolidated Electronics Industries Crp., Jackson, Mich., a corporation of Delaware Application July 8, 1954, Serial No. 442,061

4 Claims. (Cl. 161-15) hand and a second hand, all of which rotate in a timing operation but which are rapidly reset for subsequent tim ing operations.

A further object of the present invention is to provide a reset clock which is driven by a reversible motor through a gear train arranged so as to drive each of the i stop clock pointers in a timing sequence when the motor rotates in one direction and upon reversal of the direction of rotation of the motor to reset the pointers rapidly to the zero position of the stop clock. v

A further object of the present invention isto provide a reset clock which has the slippage means as well as the reset arms and locking teeth arranged on one shaft. 1 His a further object of the present invention to substantially eliminate the inaccuracies caused by the change in load on the governed motorthereby affecting its governing action. This is of great importance when the stop clock mechanism changes from idling to timing operation. Therefore, in order to substantially eliminate the aforesaid inaccuracies a load equal to the timing load is incorporated in the clutch. This equalizes the motor load for both the idling and timing periods leaving the governor virtually unaffected during the operation of the present stop clock mechanism.

The above and other features, objects and advantages of the present invention will be fully understood from the following description considered in connection with the accompanying illustrative drawings.

Fig. 1 is a side elevational view of the reset mechanism embodying the present invention being partly in section,

Fig. 2 is a top plan fragmentary view illustrating a reset arm and a locking tooth employed in the present invention,

Fig. 3 is a fragmentary front elevation view of the elements shown in Fig. 2,

Fig. 4 is a fragmentary front elevation view of a friction finger embracing the lower shaft of the present reset mechanism,

' Fig. 5 is a side elevational view of a modification of the reset mechanism embodying the present invention, being partly in section,

Fig. 6 is a diagramamtic view of the reset finger employed in the modification of the present invention shown in Fig. 5,

Fig. 7 is a perspective view of the friction element utilized in the modification of the present invention shown in Fig. 5.

Patented Jan. 20, 1959 ice Referring to the drawings and more particularly to Fig. 1 the stop clock embodying the present invention comprises a frame 8 and a gear train assembly therein preferably driven by a reversible motor 10, provision being made in the motor drive for some lost motion during reset operation in order to prevent the stalling of the motor on reset and to prevent damage to the gears. The motor 10 through suitable clutching mechanism drives a shaft 12 on which is mounted a series of gears, pinions and other elements which will hereinafter be disclosed in detail.

The clutching mechanism or driving connection which as indicated is of the slip type, that is it provides for some lost motion during reset operation, is indicated in general by the reference numeral 22 and may be the same as that specifically described below in connection with Figure 5.

On the extreme free end of the shaft 12 and in front of a dial face 14 are three pointers 16, 18 and 20 respectively. Pointer 16 is what I term the hour hand in that it rotates once each hour, while pointers 18 and 20 are what I term the minute and second hands respectively in that they rotate once each minute and once each second respectively. A shaft 13 is positioned parallel to shaft 12 and mounted on both ends in frame 8. The pinion 28 fixedly mounted on shaft 12 engages gear 30 which is freely mounted on shaft 13 to rotate the latter in a counter-clockwise direction. A pinion 32 is loosely mounted on shaft 13 and has an integral extension 34 provided with a smooth circumference. Gear 36 fixediy mounted on hollow shaft 12a (freely mounted on shaft 12) is driven by pinion 32 and is operative to drive the minute hand 18 which is fixedly secured on the end of shaft 12a. Likewise, the hour hand 16 which is fixedly secured to the end of a hollow shaft 12!) is driven by the gear 42 also fixedly mounted on shaft 12b through pinion 40 which is loosely mounted on the lower shaft 13 and counter-clockwise rotating gear 38 loosely mounted on shaft 13, which in turn is driven by pinion 3'7 fixedly mounted on shaft 12a. Pinion 40 is provided with an extension 41 similar in construction to extension 34 hereinbefore discussed.

In operation, pointer shafts 12, 12a and 12b rotate together with the gears thereon in a clockwise direction. The gear ratio arrangements cause the pointers to rotate in a certain sequence relative to each other to thereby give directreadings on the dial face in fractions of an hour, or minutes ointer 16), fractions of a minute, or seconds (pointer 18) and fractions of a second (pointer 20).

Shafts 12, 12a and 12b have preferably three similar reset arms 44, 46 and 48 respectively mounted thereon which take the form of curved, flexible springs (see Fig. 3 for shape of arms). On gears 36 and 42 are positioned wedge- shaped locking teeth 50 and 52. It is to be noted that it is within the scope of the invention to alternately make the teeth integral, or separate from the gear but affixed thereto. An additional locking tooth 54 similar in shape to teeth 50 and 52, is secured to the frame 8 (see Fig. 2 for shape of teeth).

When the shafts 12, 12a and 12b rotate in the clockwise direction and the stop clock is timing, the reset arms all ride over the upwardly sloping sides of the wedgeshaped locking teeth. However, when the motor 10 is reversed, the reset arms rotate counterclockwise until the arms abut against a side of each of said locking teeth which is perpendicular to the plane of gears 36 and A pair of friction fingers 56 and 58 are fixed to the gears 30 and 38 respectively. The aforesaid friction fingets may be bifurcated so that the arms thereof may surround a portion of each of the extensions 34 and 41 of pinions 32 and 40, respectively and grasp the same.

Thus, on direct drive both the friction fingers 56 and 58 grasp the extensions 34 and 41 in order to transmit the direct driving power of the motor ft to the pinions 32 and 49 from gears 36 and 38. However when the direction of rotation of the motor is reversed the friction fingers 56 and 58 slip on extensions 34 and 61 thus permitting the pinions 32 and 40 to move relative to gears 30 and 3t, and all the pointers to revolve back to their starting positions substantially at a rate of l R. P. S. (the rate of shaft 12). In this regard, it should be noted that in the normal timing operation the pointer 16 revolves around the dial face 14 at the rate of 1 R. P. 1-1., the pointer 18 at the rate of 1 R. P. M., and the pointer 20 at the rate of l R. P. S. Yet in the resetting operation all the pointers are reset to their starting position in no more than three seconds by reason of the fact that shafts 12a and 12b are driven directly from shaft 12 through reset arms .4 and 46. The fixed locking tooth 54 on the frame 3 determines the commencement point of the timing sequence for pointer 16 and the other pointers 18 and 21 respectively are brought into alignment with the pointer 16 and in superposed relation thereto, the location of stoppage of the gears and pinions of the device being determined by the reset or commencement position of gear 42. When the pointers have all reached their reset positions the gears of the device will not be damaged and the motor will not be stalled since there is provision made, as indicated, in the drive for lost motion or slip which will overcome the aforesaid prospective dangers and give the operator time to either put the motor in direct drive or stop the same.

Referring now to Fig. 5 there is shown an alternative embodiment of the invention wherein shaft 60 is rotated by a reversible motor 62 and a shaft 64 is positioned parallel to and below shaft 60. The driving connection between the motor 62 and shaft 60 is, as is that in the previous embodiment, of the slip clutch variety and contains provision for continuing loading of the motor. Upon the output shaft 91]) of motor 62 is fixed a collar member $1 containing a circumferential groove 92, the latter being adapted to be continually engaged by a friction clip 93 secured to a pin 94 on a fly wheel 95. Fly wheel 95 is fixedly secured to what may be termed the input end of shaft 69 and is provided with a bearing 96 in which the free end of output shaft 9 of motor 62 may be rotatably received. The normal friction developed by the friction clip 93 and collar member 91 is sufficient to provide a driving connection between the collar and the fiy wheel 95 and hence between shaft 90 and shaft 60.

Shafts 6t) and 64 are similar in construction to shafts 12 and is or ilgLifC l and the operation of the pointers through the gears and pinions mounted on shafts 6d and 6 is the same as described in connection with the construction shown in Fig. 1 except that a friction element 66 is fixedly mounted on the hub 76 of a hollow shaft 75 which is in turn mounted loosely on shaft 69. Element 66 is bifurcated at one end 68 and is provided with an upwardly-sloping portion 67. Fixedly mounted on shaft 6!) is a curved spring-like reset finger member 70 which in clockwise rotation of the shaft 69 rides over the upwardly-sloping portion 67 of bifurcated end 6? of element 66. However upon counter-clockwise rotation of the shaft the member 76 engages the underside of upwardly-sloping portion 67 of element 66. Thus, the element 66 and the member itl take the place of the reset arm and the locking tooth, e. g. 46 and 52, as shown in Fig. 1. it should be noted that the member 70 is rigidly connected to a ointer 72 through shaft 6% while element 66 is rigidly connected to a pointer 74 through hollow shaft 75. Thus, on reset of the clock mechanism, the member '78 in reversing carries along the pointer 72 While the e it 25 carries the pointer '74 along with it thereby both pointers '72 and 74 to their starting or zero position which is established by a tooth 38 on the frame and reset arm 84 fixedly secured on shaft 75. Pointer 72 is the fast pointer mounted directly on shaft while pointer 74 is the slow pointer mounted directly on hub 76 of shaft 75. A gear A is loosely mounted on hub 76 of the slow pointer assembly. Freely mounted on shaft 64 is a pinion 65 which is driven by gear tit), fixed thereto, from a pinion 73 fixed to shaft 60. Pinion 65 drives the slow pointer assembly because of the friction applied at B (a friction pad frictionally connecting gear A and hub 76) and C (area of frictional engagement of friction element 66 and gear A) in the clockwise rotation of the entire assembly. During reset operation, however, when shaft 60 is driven in the reverse direction, the assembly slips at B and C to permit a rapid reset of the aforesaid pointers to the zero starting position. Fig. 6 shows the reset finger member and the upwardly sloping portion 67 of bifurcated end 68 of friction element 66 in one position in the resetting se quence according to the present invention. It is to be noted that in the timing sequence the member 70 climbs and passes over the upwardly-sloping portion 67 while in the resetting sequence (Fig. 6) the member 70 is observed engaging the underside of upwardly-sloping portion 67 to carry element 66 together with pointer 74 at the speed rate of the fast pointer 72 in a counter-clockwise direction until the zero reset position determined by tooth 83 is attained.

While I have shown and described the preferred embodiment of my invention, it will be understood that the latter may be embodied otherwise than as herein specifically illustrated or described and that in the illustrated embodiment certain changes in the details of construction and in the arrangement of parts may be made without departing from the underlying idea or principle of the invention within the scope of the appended claims.

What I claim is:

1. A reset mechanism for a stop clock comprising a reversible motor, two pointer shafts, means operatively connecting one pointer shaft to said motor, one of said pointer shafts being hollow and having the other pointer shaft positioned concentrically therein, a gear assembly mounted on each of said pointer shafts, a dial face plate having an aperture therein, one end of each of said pointer shafts projecting through said aperture, a pointer mounted on said one end of each of said pointer shafts and in front of said dial face plate, a secondary shaft spaced from said pointer shafts, a pinion and gear assembly mounted on said secondary shaft and operatively connected to said gear assemblies of both of said pointer shafts, at least one locking element for each of said pointer shafts, a reset arm operatively attached to each of said pointer shafts and so constructed and arranged that when said pointer shafts rotate in one direction said reset arms pass over said locking elements and when said pointer shafts rotate in an opposite direction said reset arms engage said locking elements to rotate said pointers together and return them only so far as their starting positions where they are in effect in locked condition, against further movement, by the locking elements, said operative connection between said pinion and gear assembly on said secondary shaft and the gear assembly on one of said pointer shafts including a friction member mounted to engage the face of a gear of said pinion and gear assembly and said last mentioned gear assembly, and means to provide lost motion between said motor and the pointer shaft to which the motor is operatively connected when said motor is operating against said locked condition of the pointers.

2. A reset mechanism for a stop clock comprising a reversible motor, a pointer shaft operatively connected to said motor, a first pinion and gear assembly mounted on said pointer shaft, a dial face plate having an aperture therein, one end of said pointer shaft projecting through said aperture, at least two pointers mounted on said one end and in front of said dial face plate, a secondary shaft spaced from said pointer shaft, a second pinion and gear assembly mounted on said secondary shaft and operatively connected to said first pinion and gear assembly, a locking tooth on the gear of said first pinion and gear assembly, a corresponding reset arm for said locking tooth secured to said pointer shaft, said reset arm and said locking tooth being so constructed and arranged that when said pointer shaft rotates in one direction said reset arm passes over said locking tooth and when said pointer shaft rotates in an opposite direction said reset arm engages said locking tooth to rotate the pointers counterclockwise and back to their starting position together, and a friction device carried by and interconnecting the gear and pinion of said second pinion and gear assembly on said secondary shaft, said friction device being so constructed and arranged that in one direction of rotation of said motor said friction device drivingly interconnects the pinion and gear mounted on said secondary shaft positively and in the other direction of rotation of said motor permits said last-mentioned pinion to slip relative to said last-mentioned gear to permit a rapid reset of said pointers.

3. A reset mechanism according to claim 2 in which said friction device comprises a pair of friction fingers mounted on the gear supported on the secondary shaft and an integral extension of the pinion mounted on said secondary shaft, the friction fingers frictionaliy engaging said integral extension.

4. A reset mechanism according to claim 1 in which the pinion and gear on said secondary shaft are fixed with respect to each other and one of said gears on a pointer shaft is frictionally mounted thereon to provide in a reset operation for relative movement between it and its pointer shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,563,770 Marden Dec. 1, 1925 2,109,352 Hazard Feb. 22, 1938 2,730,913 Friedman Jan. 17, 1956

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